Evaluation of Bone Mineral Changes in Panoramic Radiographs of Hypothyroid and Hyperthyroid Patients Using Fractal Dimension Analysis

Objective Hyperthyroidism and hypothyroidism are endocrinopathies that cause a decrease in bone mineral density. The aim of this study is to investigate possible bone changes in the mandible caused by hyperthyroidism and hypothyroidism using fractal analysis (FA) on panoramic radiographs. Material and Methods Panoramic radiographs of a total of 180 patients, including 120 patient groups (60 hyperthyroid, 60 hypothyroid) and 60 healthy control groups, were used. Five regions of interests (ROI) were determined from panoramic radiographs and FA was performed. ROI1: geometric midpoint of mandibular notch and mandibular foramen, ROI2: geometric midpoint of mandibular angle, ROI3: anterior of mental foramen, ROI4: basal cortical area from distal mental foramen to distal root of first molar, ROI5: geometric center of mandibular foramen and mandibular ramus. Results While a significant difference was observed between the patient and control groups regarding ROI1 and ROI2 (p < 0.05); there was no significant difference between the groups in relation to ROI3, ROI4, and ROI5. All FA values were lower in the hyperthyroid group than in the hypothyroid group. Conclusion Fractal analysis proves to be an effective method for early detection of bone mass changes. In the present study, it was concluded that while the mandibular cortical bone was intact, trabecular rich regions were affected by osteoporosis caused by thyroid hormones. Necessary precautions should be taken against the risk of osteoporosis in patients with thyroid hormone disorders.

The Role of Nuclear Medicine in Benign Thyroid Disease

Since the mid-twentieth century, the radionuclide thyroid scan has been utilized in the management of benign thyroid disorders. In current medical practice, patients with hyperthyroidism are referred for thyroid scintigraphy, while patients with goiters and thyroid nodules are most often evaluated by ultrasound or computed tomography. Since thyroid scintigraphy reflects the functional state of the gland, it provides information that anatomical imaging lacks. Therefore, radionuclide imaging of the thyroid is the imaging modality of choice in the evaluation of the hyperthyroid patient. In addition, patients with so-called subclinical hyperthyroidism often present a diagnostic dilemma to the clinician since the causative factor must be determined for proper patient management. The aim of this manuscript is to illustrate the imaging characteristics of thyroid disorders commonly seen in clinical practice resulting in thyrotoxicosis or pending thyrotoxicosis, so that correlation with clinical presentation and pertinent laboratory data will lead to the correct diagnosis.

Effect of iodinated radiographic contrast media on radioimmunoassay for measuring thyroid hormones

Radioimmunoassay (RIA) is one of the most routine laboratory tests for diagnosing thyroid disease. Patients might receive iodine in the form of intravenous iodinated radiographic contrast media (IRCM) before testing of serum thyroxin (T4) or triiodothyronine (T3) concentration by RIA. The objective was to determine the effect of IRCM on T4 and T3 hormone tests in normal, hypothyroid, and hyperthyroid hormone conditions by RIA. IRCMs (0, 2.5, 5 and 10 mgI/mL) used in this study were iopromide and iodixanol. RIA was determined by commercial T4 RIA kit and T3 RIA kits. The method suggested by the manufacturer was followed. Normal, hypothyroid, and hyperthyroid hormones condition were 1.2 ng/mL, 0.2 ng/mL and 2.2 ng/mL for T3 hormone concentration and 70 ng/mL, 30 ng/mL and 140 ng/mL for T4 hormone concentration, respectively. %Bound values were compared between IRCM-incubated groups and non-incubated group. The data showed that iopromide-incubated groups did not statistically significant change %bound values of T3 and T4 hormone tests in normal, hypothyroid, and hyperthyroid conditions, compared to the non-incubated group. In the same way, %bound values of T3 and T4 hormone tests in iodixanol-incubated groups did not change at all conditions when compared to the non-incubated group. This finding suggested that iodinated radiographic contrast media was unlikely to result in significant problems with radioimmunoassay for measuring T3 and T4 thyroid hormones.

Radioiodine therapy of thyroid autonomy

Radioiodine therapy (RIT) of thyroid functional autonomy (TFA) is rapidly evolving, though it has been recognized for decades as a very effective treatment of toxic nodular varieties. Indeed, TFA is a frequent cause of persistent subclinical hyperthyroidism, which should be regarded as a new metabolic syndrome, with well-established adverse cardio-vascular consequences. Sensitive TSH assays and multiparametric ultrasounds are not accurate enough to reliably diagnose TFA and identify its main variants, unifocal, multifocal (UFA/MFA) and disseminated autonomy (DISA). Modern diagnostic tools are extensively presented and rely upon Thyroid Scan imaging and quantification. A new relationship allows predicting at baseline, an excess of 123I uptake as compared to the TSH stimulation in compensated TFA. Suppressed TS are useful with either isotope, otherwise. Diagnosis of the DISA variant is presented as compared to Graves' disease. Dosimetry has some specificity in TFA work-up. Indeed, the spatial distribution of the dose is as important as the mean value itself and can be eventually controlled by adjusting the TSH level with the smart use of LT3 or antithyroid drug therapy (ATD). A review of the different ways to determine the target mass from anatomical to functional approaches is presented. Main clinical and dosimetric published results of RIT are summarized according to clinical goals. Endogenous TSH stimulation using an ATD preparation has promising results in reducing big autonomously functioning goiters. Finally, we report preliminary successful results of preventive RIT using short term LT3 suppression in compensated TFA, with low administered activities and low rate of hypothyroidism.

Update on diagnosis and treatment of hyperthyroidism: ultrasonography and functional imaging

Ultrasonography and radionuclide imaging using [^99mTc]Pertechnetate or radioactive iodine isotopes are essential tools used during the diagnostic workup of hyperthyroidism with or without structural alterations of the thyroid. Color duplex sonography and ultrasound elastography may add important information to find the cause of the hormone excess. During the last few years, hybrid imaging using SPECT/-(CT) or PET-based methods, such as [¹²⁴]Iodine-PET/CT or [¹²⁴]Iodine-PET/ultrasound have been increasingly used, playing a role in the context of localizing ectopic thyroid tissue or in multinodular goiter. Recently, promising data has been published on the use of [^99mTc]MIBI imaging in amiodarone induced hyperthyroidism.

Effects of Hyperthyroidism on Adipose Tissue Activity and Distribution in Adults

Background: Positron emission tomography (PET) has provided evidence that adult humans retain metabolically active brown adipose tissue (BAT) depots. Thyroid hormones (TH) stimulate BAT thermogenesis by central and peripheral mechanisms. However, the effect of hyperthyroidism on BAT activity and BAT volume in humans is yet not fully understood. The aim of this study was to investigate the effect of TH on (i) the metabolic activity of brown and white adipose tissue (WAT) depots, (ii) on abdominal visceral and subcutaneous adipose tissue area, and (iii) on serum levels of metabolically active cytokines. Methods: Nineteen patients with overt hyperthyroidism were investigated through repeated 2-[¹⁸F]fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (2-[¹⁸F]FDG PET/CT) in the hyperthyroid and in the euthyroid state. The 2-[¹⁸F]FDG uptake was calculated as standard uptake ratio with blood pool as reference. Fat areas were quantified by means of CT segmentation. Serum levels of fetuin A and B, fibroblast growth factor 21, adipocyte fatty acid-binding protein (AFABP), retinol-binding protein 4, pro-enkephalin, pro-neurotensin, and neuregulin 4 were determined in the hyperthyroid and in the euthyroid state for each subject. Results: 2-[¹⁸F]FDG uptake was increased in the hyperthyroid state in BAT in comparison with the euthyroid phase (p = 0.001). There was no correlation between serum free triiodothyronine (fT3) and free thyroxine (fT4) levels and 2-[¹⁸F]FDG uptake in BAT or WAT. In the hyperthyroid state, fT3 levels were positively associated with skeletal muscle standardized uptake value ratios. Areas of visceral adipose tissue and skeletal muscle were significantly decreased in hyperthyroidism. AFABP levels correlated positively with fT3 (p = 0.031, β = 0.28) and fT4 (p = 0.037, β = 0.27) in the hyperthyroid state. Conclusions: Our results suggest that the contribution of increased TH levels to the glucose uptake of BAT and WAT is low compared with that of the skeletal muscle. Hyperthyroid subjects have reduced areas of visceral adipose tissue and increased AFABP levels.

Thyroid function and non-alcoholic fatty liver disease in hyperthyroidism patients

BACKGROUND

Although thyroid function has been demonstrated to be associated with non-alcoholic fatty liver disease (NAFLD) in different population, the prevalence and features of NAFLD in hyperthyroidism have not been reported. The present study aims to investigate the prevalence of NAFLD and association of thyroid function and NAFLD in hyperthyroidism patients.

METHODS

This cross-sectional study was performed in Zhongshan Hospital, Fudan University, China. A total 117 patients with hyperthyroidism were consecutively recruited from 2014 to 2015. Thyroid function and other clinical features were measured, liver fat content was measured by color Doppler ultrasonically, NAFLD was defined in patients with liver fat content more than 9.15%. Statistical analyses were performed with SPSS software package version 13.0.

RESULTS

The prevalence of NAFLD was 11.97% in hyperthyroidism. Patient with NAFLD had lower free triiodothyronine (FT3) and free thyroxine (FT4) levels than patients without NAFLD (P < 0.05). After adjusting for age, gender, metabolic parameters and inflammation factors, higher FT3 were associated with lower liver fat content (β = - 0.072, P = 0.009) and decreased odds ratio of NAFLD (OR = 0.267, 95%CI 0.087-0.817, P = 0.021).

CONCLUSIONS

FT3 level was negatively associated with the liver fat content in this population. These results may provide new evidence in the role of thyroid hormone on the regulation of liver fat content and NAFLD.

Impact of Radioiodine Treatment on Doppler Flow Parameters in the Central Retinal Artery and Ophthalmic Artery in Patients With Hyperthyroidism

OBJECTIVES

The aim of this study was to identify changes in Doppler flow parameters in the central retinal artery (CRA) and ophthalmic artery (OA) that could be indicative of de novo development of thyroid-associated orbitopathy in the early period after radioiodine treatment.

METHODS

Eighty-two patients with hyperthyroidism were enrolled: 44 with Graves disease and 38 with toxic nodular goiter. In both groups, blood flow parameters in the CRA and OA were analyzed before and 2 and 4 weeks after radioiodine administration. The peak systolic velocity and end-diastolic velocity (EDV) were evaluated, and the resistive index (RI) was calculated.

RESULTS

There were no statistically significant differences in the peak systolic velocity, EDV or RI between groups at baseline and 4 weeks after radioiodine administration. Two weeks after radioiodine administration, the RI in the CRA (P = .034) and EDV in the OA (P = .026) were significantly lower, and the EDV in the CRA (P = .004) was higher in patients with Graves disease than in patients with toxic nodular goiter. There was an inverse correlation between baseline thyrotropin receptor autoantibody (TRAb) levels and the difference between the RI at weeks 4 and 2 (RI3-RI2) in the CRA (r = -0.458; P < .05) and a positive correlation between the baseline anti-thyroid peroxidase antibody concentration and RI3-RI2 in the OA (r = 0.435; P < .05).

CONCLUSIONS

Administration of radioiodine results in more prominent features of hyperkinetic circulation. Patients with Graves disease and high TRAb titers have a lower sensitivity to radioiodine treatment. High TRAb titers suggest higher disease activity and a weaker therapeutic effect of radioiodine.

Pre-operative imaging workup for surgical intervention in primary hyperparathyroidism: A tertiary referral center experience

PURPOSE

Preoperative imaging in patients with primary hyperparathyroidism provides important localization information, allowing the surgeon to perform a focused surgery. However there are no evidence-based guidelines suggesting which preoperative imaging should be used, resulting in a risk of excessive prescription of exams and waste of economic resources. The main purpose of this study was to describe our experience on the performance of various imaging techniques for the preoperative localization of abnormal parathyroid gland/s, with a focus on the sensitivity and specificity of each technique. Secondly, we carried out an analysis of the cost utility of each technique in order to determine the most clinical and cost-effective combination of localization studies.

MATERIALS AND METHODS

Records of 336 patients who underwent parathyroidectomy were retrospectively examined comparing imaging and intraoperative/histopathologic findings to evaluate the accuracy in parathyroid detection of each imaging technique. Costs were determined by regional health system reimbursement.

RESULTS

We found that the sensitivity of color Doppler US was significantly higher than SPECT (p 0,023), while the sensitivity of 4D-CT was significantly better than US (p 0,029) and SPECT (p 0,0002).

CONCLUSIONS

In experienced hands color Doppler US is a highly sensitive technique especially in patients with no thyroid diseases. In patients with concomitant thyroid pathology, the combination of US and 4D-CT represents a reliable localization technique.

Effects of Thyroid Function on Phosphodiester Concentrations in Skeletal Muscle and Liver: An In Vivo NMRS Study

CONTEXT

Thyroid function is clinically evaluated by determination of circulating concentrations of thyrotropin (thyroid-stimulating hormone; TSH) and free thyroxine (fT4). However, a tissue-specific effector substrate of thyroid function is lacking. Energy-rich phosphorus-containing metabolites (PM) and phospholipids (PL) might be affected by thyroid hormone action and can be noninvasively measured by 31P nuclear magnetic resonance spectroscopy (NMRS).

OBJECTIVES

To measure the actions of peripheral thyroid hormones on PM and PL tissue concentrations.

DESIGN AND SETTING

A longitudinal, prospective pilot study was performed.

PARTICIPANTS

Nine patients with hyperthyroidism (HYPER) and 4 patients with hypothyroidism (HYPO) were studied at baseline and 3 months after treatment.

MAIN OUTCOME MEASURES

High-field 1H/31P NMRS was used to assess profiles of PM, PL, and flux through oxidative phosphorylase in liver and skeletal muscle, as well as ectopic tissue lipid content.

RESULTS

The concentrations of total skeletal muscle (m-) and hepatic (h-) phosphodiesters (PDE) and one of the PDE constituents, glycerophosphocholine (GPC), were lower in HYPER compared with HYPO (m-PDE: 1.4 ± 0.4 mM vs 7.4 ± 3.5 mM, P = 0.003; m-GPC: 0.9 ± 0.3 mM vs 6.7 ± 3.5 mM, P = 0.003; h-PDE: 4.4 ± 1.4 mM vs 9.9 ± 3.9 mM, P = 0.012; h-GPC: 2.2 ± 1.0 mM vs 5.1 ± 2.4 mM, P = 0.024). Both h-GPC (rho = -0.692, P = 0.018) and h-GPE (rho = -0.633, P = 0.036) correlated negatively with fT4. In muscle tissue, a strong negative association between m-GPC and fT4 (rho = -0.754, P = 0.003) was observed.

CONCLUSIONS

Thyroxine is closely negatively associated with the PDE concentrations in liver and skeletal muscle. Normalization of thyroid dysfunction resulted in a decline of PDE in hypothyroidism and an increase in hyperthyroidism. Thus, PDE might be a sensitive tool to estimate tissue-specific peripheral thyroid hormone action.

Changes in left ventricular function and contractile homogeneity in young adults with newly diagnosed hyperthyroidism due to Graves' disease

PURPOSE

The aim of this study was to investigate myocardial dysfunction and mechanical abnormalities in young patients with Graves' disease before therapy, using two-dimensional speckle tracking echocardiography.

METHODS

We performed a comprehensive transthoracic echocardiographic examination, including segmental and global radial strain, and time-to-peak radial strain, in 47 young patients with hyperthyroidism and 34 healthy adults. The time-to-peak radial strain was corrected by RR interval. The variables derived from radial myocardial deformation by the six-basal, six-mid, and six-apical segmental model were compared to investigate the difference of the myocardial function between the two groups.

RESULTS

Early diastolic mitral inflow velocity, E/A ratio, early diastolic mitral annular velocity, and e'/a' ratio were lower in patients with Graves' disease than in controls. The left ventricular end-diastolic volume, left ventricular end-systolic volume, stroke volume, cardiac output, heart rate, late diastolic mitral inflow velocity, and late diastolic mitral annular velocity were slightly higher in patients than in controls. Radial strain, global radial strain, and corrected time-to-peak radial strain were lower in the patient group.

CONCLUSIONS

The decreased radial strain, global radial strain, and corrected time-to-peak radial strain in young patients with newly diagnosed hyperthyroidism due to Graves' disease could serve as an early sign of subclinical cardiac involvement.

Efficacy and Safety of Long-Term Universal Salt Iodization on Thyroid Disorders: Epidemiological Evidence from 31 Provinces of Mainland China

Background: Mandatory universal salt iodization (USI) has been implemented in China for 20 years. Although iodine deficiency disorders are effectively controlled, the risk of excess iodine have been debated. Methods: A nationally representative cross-sectional study with 78,470 enrolled participants, aged 18 years or older, from all 31 provincial regions of mainland China was performed. The participants were given a questionnaire and underwent B-mode ultrasonography of the thyroid. Serum concentrations of thyroid hormones, thyroid antibodies, and urine iodine concentration (UIC) were measured. Results: The median UIC of the adult population was 177.89 μg/L. The weighted prevalence of thyroid disorders in adults were as follows: 0.78% of overt hyperthyroidism, 0.44% of subclinical hyperthyroidism, 0.53% of Graves' disease, 1.02% of overt hypothyroidism, 12.93% of subclinical hypothyroidism, 14.19% of positive thyroid antibodies, 10.19% of positive thyroid peroxidase antibodies, 9.70% of positive thyroglobulin antibodies, 1.17% of goiter, and 20.43% of thyroid nodules. Iodine excess was only associated with higher odds of overt hyperthyroidism and subclinical hypothyroidism, while iodine deficiency was significantly associated with higher odds of most thyroid disorders. In addition, increased iodine intake was significantly associated with elevated serum thyrotropin levels but was inversely associated with thyroid antibodies and thyroid nodules. Conclusions: The long-term mandatory USI program with timely adjustments is successful in preventing iodine deficiency disorders, and it appears to be safe. The benefits outweigh the risks in a population with a stable median iodine intake level of up to 300 μg/L.

Ectopic pituitary adenoma of the TSH-secreting sphenoidal sinus with excellent response to somatostatin analogs. Theory of the embryogenesis and literature review from a clinical case

Ectopic thyrotropin-secreting pituitary adenomas are rare, with only 10 published cases. We report the case of a 52-year-old woman who was referred for primary hypothyroidism, who showed clinical signs of hyperthyroidism and had been under treatment with levothyroxine. Her exams revealed high levels of thyroid stimulating hormone (TSH), at odds with free thyroxin (FT4) and raised triiodothyronine (T3), which remained elevated after medication suspension, suggesting possible central hyperthyroidism. Sellar MRI showed normal pituitary gland, with a mass in the sphenoid sinus of 24 mm. A possible ectopic TSH secreting pituitary tumor of sphenoid sinus was hypothesized. After a intramuscularly (IM) single dose of a sustained-relase of a somatostatin analog (octreotide) 20 mg, plasma levels of thyroid hormones were normalized and a significant tumor reduction was demonstrated in MRI control at 7-weeks' follow-up. The tumor was removed by transsphenoidal endoscopy, and the biopsy confirmed an adenoma with positive immunostaining for TSH and GH. Hyperthyroidism recurrence was observed in hormonal controls 4 weeks after surgery. Treatment with sustained-release octreotide was reinitiated, every 60-days for two years, with normalization of the thyroid hormone profile, but with a residual lesion with the appearance of a tumor in the MRI. A second tumor resection was performed, achieving sustained hormonal cure and no residual tumor lesion at 2-years' follow-up. To our knowledge, this is the first report of an ectopic thyrotropin-secreting pituitary adenoma of the sphenoid sinus. Clinical and laboratory aspects relevant to this entity are reviewed, emphasizing the usefulness of octreotide in the management of the reported case.

A review of the propriety of thyroid ultrasound referrals and their follow-up burden

PURPOSE

The overdiagnosis of thyroid nodules and indolent thyroid cancers represents an increasing burden on health services, with thyroid ultrasound (US) imaging often representing the initial entry point into the thyroid nodule diagnostic pathway. The aim of this study was to retrospectively review thyroid US referrals to a single Irish hospital to determine if the stated indications for imaging had been appropriate, to review the results of the scans, and to assess the follow-up required in each case.

METHODS

Patient demographics, scan indications, results, and outcomes were retrospectively reviewed for all patients undergoing thyroid ultrasound from 2012 to 2016. Data were analyzed using GraphPad Prism and expressed in mean ± standard deviation.

RESULTS

In total, 318 patients (mean age 53 ± 15 years, 85% female) had at least one ultrasound. Most US scans were performed for appropriate indications in order to follow up known thyroid nodular disease and/or malignancy (34.3%), to assess new thyroid goiters or discrete neck lumps (33.3%), and to follow up incidental findings from other imaging modalities (12.6%). However, scans were also requested (in the absence of any palpable goiter or mass) for choking/neck pain/swallowing complaints (12.3%), hypo/hyperthyroidism (6.6%), and miscellaneous reasons (0.6%) that were deemed either potentially or likely inappropriate. Of these scans, approximately half of the identified nodule(s) were deemed unlikely to be related to the stated symptoms, but which subsequently required follow-up imaging ± biopsy. No cases of malignancy were identified.

CONCLUSIONS

In our center, a significant percentage of thyroid US scans along with their subsequent follow-up were potentially avoidable.

Utility of systematic TSHR gene testing in adults with hyperthyroidism lacking overt autoimmunity and diffuse uptake on thyroid scintigraphy

OBJECTIVE

Patients with hyperthyroidism lacking autoimmune features but showing diffuse uptake on thyroid scintigram can have either Graves' disease or germline activating TSH receptor (TSHR) mutation. It is important to identify patients with activating TSHR mutation due to treatment implication, but the overlapping clinical features with Graves' disease make it difficult to discriminate these two conditions without genetic testing. Our study aimed to assess the potential of systematic TSHR mutation screening in adults with hyperthyroidism, showing diffuse uptake on thyroid scintigraphy but absence of TSH receptor antibodies (TRAb) and clinical signs of autoimmunity.

DESIGN

A cross-sectional study of Caucasian adults with hyperthyroidism, managed at three endocrine centres in the South West, UK, from January 2006 to April 2017.

METHODS

We recruited 78 adult Caucasian patients with hyperthyroidism showing diffuse uptake on ^99m Tc-pertechnetate thyroid scintigraphy but without TRAb and other autoimmune clinical features of Graves' disease (such as thyroid-associated ophthalmopathy or dermopathy). Genomic DNA of these patients was analysed for variants in the TSHR gene.

RESULTS

Genetic analysis identified 11 patients with four variants in TSHR [p.(Glu34Lys), p.(Asp36His), p.(Pro52Thr) and p.(Ile334Thr)]. None of these variants were pathogenic according to the American College of Medical Genetics and Genomics guideline.

CONCLUSIONS

Activating TSHR mutations are a rare cause of nonautoimmune adult hyperthyroidism. Our study does not support the routine genetic testing in adult patients with hyperthyroidism showing diffuse uptake on scintigraphy but negative TRAb and lacking extrathyroidal manifestations of Graves' disease.

Dysregulation within the salience network and default mode network in hyperthyroid patients: a follow-up resting-state functional MRI study

This study investigated the aberrant connectivity of the salience network (SN) and default mode network (DMN) and the relevance between these abnormalities and symptom improvement in hyperthyroid patients using resting-state functional magnetic resonance imaging (rs-fMRI). Seed-based functional connectivity (FC) analyses were performed on state fMRI data to reveal possible differences in critical node connectivity in the SN and DMN between 41 new-onset, untreated hyperthyroid patients and 41 healthy controls. Subsequently, follow-up data were available for 25 patients treated with methimazole for one month. Compared with the healthy controls, the patients exhibited abnormal internetwork FC from the SN to the DMN and the executive control network (ECN) and decreased intra-network FC within the SN. Relative to the hyperthyroid state, the antithyroid therapy induced reversible connectivity of the left insula to the dorsal anterior cingulate cortex(dACC)and ECN, and persistently increased connectivity between the SN and DMN in patients with improved thyroid function. Finally, Pearson's correlation analyses were performed among the abnormal FC, neuropsychological assessment and serum free triiodothyronine(FT3)level data. The results indicated that aberrant intra- and internetwork FC in the SN and DMN might underlie the pathogenesis of hyperthyroidism, and antithyroid treatment could regulate the FC of certain key brain regions within the SN and DMN in hyperthyroid patients.

Hyperthyroidism in Elderly Patients with Atrial Fibrillation and Normal Thyroid Hormone Measurements

The results of a study to investigate possible underdiagnosis of hyperthyroidism in the elderly are reported. Four out of 24 patients with atrial fibrillation for which there was no obvious cause and who had normal thyroid hormone measurements were found to have subnormal thyrotropin responses to thyrotropin-releasing hormone and abnormal thyroid scans. The implications of this finding are discussed.

De novo SOX10 Nonsense Mutation in a Patient with Kallmann Syndrome, Deafness, Iris Hypopigmentation, and Hyperthyroidism

Kallmann syndrome (KS) is a clinically and genetically heterogeneous disorder characterized by hypogonadotropic hypogonadism and olfactory dysfunction. Recently, mutations in SOX10, a well-known causative gene of Waardenburg syndrome (WS), have been identified in a few KS patients with additional developmental defects including hearing loss. However, the understanding of SOX10 mutation associates with KS and other clinical consequences remains fragmentary. A 30-year-old Chinese male patient presented with no pubertal sex development when he was at the age of twelve years. Additionally, he showed anosmia, sensory deafness, and blue irises. Last year, he developed clinical symptoms of hyperthyroidism with a fast heartbeat, heat intolerance and weight loss. Blood examinations revealed low levels of FSH, LH, and testosterone. Thyroid function showed high levels of FT3, FT4 and extremely low level of TSH. Molecular analysis detected a de novo (c.565G>T/p.E189X) mutation in SOX10, which has previously been reported in a patient with WS4 (WS with Hirschsprung). The mutation was predicted to be probably damaging. These results highlight the significance of SOX10 haploinsufficiency as a genetic cause of KS. Importantly, our result implies that the same SOX10 mutation can underlie both typical KS and WS, while the correlation between SOX10 and hyperthyroidism still needs to be clarified in the future.

Opposing Effects of Maternal Hypo- and Hyperthyroidism on the Stability of Thalamocortical Synapses in the Visual Cortex of Adult Offspring

Insufficient or excessive thyroid hormone (TH) levels during fetal development can cause long-term neurological and cognitive problems. Studies in animal models of perinatal hypo- and hyperthyroidism suggest that these problems may be a consequence of the formation of maladaptive circuitry in the cerebral cortex, which can persist into adulthood. Here we used mouse models of maternal hypo- and hyperthyroidism to investigate the long-term effects of altering thyroxine (T4) levels during pregnancy (corresponding to embryonic days 6.5-18.5) on thalamocortical (TC) axon dynamics in adult offspring. Because perinatal hypothyroidism has been linked to visual processing deficits in humans, we performed chronic two-photon imaging of TC axons and boutons in primary visual cortex (V1). We found that a decrease or increase in maternal serum T4 levels was associated with atypical steady-state dynamics of TC axons and boutons in V1 of adult offspring. Hypothyroid offspring exhibited axonal branch and bouton dynamics indicative of an abnormal increase in TC connectivity, whereas changes in hyperthyroid offspring were indicative of an abnormal decrease in TC connectivity. Collectively, our data suggest that alterations to prenatal T4 levels can cause long-term synaptic instability in TC circuits, which could impair early stages of visual processing.

Relationship between the abnormal diastolic vortex structure and impaired left ventricle filling in patients with hyperthyroidism

Intraventricular hydrodynamics plays an important role in evaluating cardiac function. Relationship between diastolic vortex and left ventricular (LV) filling is still rarely elucidated. The aim of this study was to evaluate the evolution of vortex during diastole in hyperthyroidism (HT) and explore the alteration of hydromechanics characteristics with sensitive indexes.Forty-three patients diagnosed with HT were classified into 2 groups according to whether myocardial damage existed: simple hyperthyroid group (HT1, n = 21) and thyrotoxic cardiomyopathy (HT2, n = 22). Twenty-seven age- and gender-matched healthy volunteers were enrolled as the control group. Offline vector flow mapping (VFM model) was used to analyze the LV diastolic blood flow patterns and fluid dynamics. Hemodynamic parameters, vortex area (A), circulation (C), and intraventricular pressure gradient (ΔP), in different diastolic phases (early, mid, and late) were calculated and analyzed.HT2, with a lower E/A ratio and left ventricular ejection fraction (LVEF), had a larger left atrium diameter (LAD) compared with those of the control group and HT1 (P < .05). Compared with the control group, the vortex size and strength, intraventricular pressure gradient during early and mid-diastole were higher in HT1 and lower in HT2 (P < .05). And in late diastole, the vortex size and strength, intraventricular pressure gradient of HT2 became higher than those of the control group (P < .05). Good correlation could be found between CE and E/A (P < .05), CM and ΔPM (P < .01), CL and FT3 (P < .05).VFM is proven practical for detecting the relationship between the changes of left ventricular diastolic vortex and the abnormal left ventricular filling.

Electrocardiographic and scintigraphic evaluation of patients with subclinical hyperthyroidism during workout

Subclinical hyperthyroidism (sHT) was found to be associated with elevated heart rate, blood pressure and increased risk of extrasystoles. However, the full clinical relevance of morphological and functional implications of sHT on the cardiovascular system is still a matter of debate. The aim of the study was to prospectively assess the influence of endogenous sHT on exercise capacity and cardiac function during workout with the use of exercise electrocardiography (ExECG) and perfusion scintigraphy. The studied group consisted of 44 consecutively recruited patients diagnosed with sHT. In all patients, ExECG, followed by post-exercise myocardial perfusion imaging, was performed. Both ExECG and scintigraphy were performed twice-in the state of sHT and after euthyroidism was restored. An average time period of exercise test was significantly longer in the state of euthyroidism than in sHT. An average oxygen consumption during exercise test was also higher after euthyroidism was achieved when compared to sHT. The end-diastolic and end-systolic volume indexes, stroke volume index and cardiac index were significantly larger in patients with sHT if compared values achieved after euthyroidism restoration. Stroke volume index was negatively correlated with TSH, and positively with free thyroid hormones values in the state of sHT, before euthyroidism was achieved. Cardiac index was positively correlated with free thyroid hormones levels. The obtained results indicate worse physical capacity in subjects with sHT and improvement of several parameters assessed during ExECG and perfusion scintiscan after therapy. Observed changes might reflect the mechanism of the deleterious effect exerted by sHT on the heart.

Effect of radioactive iodine therapy on carotid intima media thickness in patients with hyperthyroidism

OBJECTIVE

The aim of this study was to evaluate the carotid intima media thickness (IMT) in patients with thyrotoxicosis who received radioactive iodine (RAI) treatment.

METHODS

This study was planned to be conducted with two different groups of people. There were 87 patients in the patient group and 98 controls. Participants were evaluated for atherosclerosis risk factors. Mean carotid IMT was measured from three consecutive traces at the common carotid artery bifurcation.

RESULTS

The mean carotid IMT was 0.81 ± 0.20 in patient group and this was higher than the controls (0.68 ± 0.19) (p < 0.01). IM thickening was positively correlated with the applied RAI dose levels in the treatment group (p = 0.029). In patients with only HT, the data of the two groups showed a significant difference, with the average IMT being higher in the patient group than that of the control group (p: 0.011).

CONCLUSION

RAI used in the treatment of thyrotoxicosis increases the IMT of carotid artery independent of age and sex. This treatment yields better results with higher doses, and this effect is more marked in patients with HT. Hence, we believe that it is necessary to calculate the dose properly for hyperthyroid cases in which treatment with RAI is planned. In particular, the patients with HT need to be treated with the minimum possible dose. Further, carotid arteries should be evaluated with US following RAI treatment.

Prevalence of silent vertebral fractures detected by vertebral fracture assessment in young Portuguese men with hyperthyroidism

BACKGROUND

Hyperthyroidism is a risk factor for reduced bone mineral density (BMD) and osteoporotic fractures. Vertebral fracture assessment (VFA) by dual-energy X-ray absorptiometry (DXA) is a radiological method of visualization of the spine, which enables patient comfort and reduced radiation exposure.

OBJECTIVES

This study was carried out to evaluate BMD and the prevalence of silent vertebral fractures in young men with hyperthyroidism.

DESIGN

We conducted a cross-sectional study in a group of Portuguese men aged up to 50 years and matched in hyperthyroidism (n=24) and control (n=24) groups.

MATERIALS AND METHODS

A group of 48 Portuguese men aged up to 50 years was divided and matched in hyperthyroidism (n=24) and control (n=24) groups. BMD (g/cm(2)) at L1-L4, hip, radius 33%, and whole body as well as the total body masses (kg) were studied by DXA. VFA was used to detect fractures and those were classified by Genant's semiquantitative method. No patient had previously been treated for hyperthyroidism, osteoporosis, or low bone mass. Adequate statistical tests were used.

RESULTS

The mean age, height, and total fat mass were similar in both groups (P≥0.05). The total lean body mass and the mean BMD at lumbar spine, hip, and whole body were significantly decreased in the hyperthyroidism group. In this group, there was also a trend for an increased prevalence of reduced BMD/osteoporosis and osteoporotic vertebral fractures.

CONCLUSIONS

The results obtained using VFA technology (confirmed by X-ray) suggest that the BMD changes in young men with nontreated hyperthyroidism may lead to the development of osteoporosis and vertebral fractures. This supports the pertinence of using VFA in the routine of osteoporosis assessment to detect silent fractures precociously and consider early treatment.

Prevalence of thyrotropin receptor germline mutations and clinical courses in 89 hyperthyroid patients with diffuse goiter and negative anti-thyrotropin receptor antibodies

BACKGROUND

We studied the frequency of thyrotropin (TSH) receptor mutations in hyperthyroid patients with diffuse goiter and negative TSH receptor antibodies (TRAb), and the clinical pictures of the hyperthyroid patients in the presence and absence of mutations.

PATIENTS AND METHODS

From 2003 through 2012, 89 hyperthyroid patients with diffuse goiter and negative TRAb based on a second- or third-generation assay underwent sequence analysis of the TSH receptor gene from peripheral leukocytes. The outcome of hyperthyroidism in patients with a TSH receptor mutation and their affected family members was compared with that in patients without any mutation after a 1-10-year follow-up.

RESULTS

Germline mutations of the TSH receptor occurred in 4 of the 89 patients (4.5%), including 3 definitive constitutively activating mutations (L512Q, E575K, and D617Y). The main difference in the clinical outcome of hyperthyroidism was that no patients with a TSH receptor mutation achieved euthyroidism throughout the follow-up, while 23.5% of patients without any mutation entered remission. The progression from subclinical to overt hyperthyroidism was not significantly different between patients with or without a mutation. Meanwhile, 10.3% of TRAb-negative patients without any TSH receptor mutation developed TRAb-positive Graves' hyperthyroidism during the follow-up.

CONCLUSIONS

The prevalence of nonautoimmune hyperthyroidism with TSH receptor mutations is lower than that of latent Graves' disease in TRAb-negative patients with hyperthyroidism. However, all affected patients with a TSH receptor mutation showed persistent hyperthyroidism regardless of subclinical or overt hyperthyroidism throughout the follow-up.

Ultrasound and color-flow Doppler evaluation for the diagnosis of subclinical hyperthyroidism

AIM

Clinical significance, population screening and management of subclinical hyperthyroidism (SHyper) are still debated. Although the diagnosis of subclinical hyperthyroidism is, by definition, purely a biochemical one a conventional gray-scale sonography and, more recently, color-flow Doppler sonography (CFDS) have proven to be useful in obtaining information about thyroid morphology and function in thyroid disease, such as SHyper. The objective of this study was to evaluate, using CFDS, the presence and significance of changes in intrathyroidal blood flow and velocity in patients affected by SHyper and, to evalutate the potential diagnostic role of CFDS in mild thyroid disease in absence of a significant alteration in the serum level of circulating thyroid hormones.

METHODS

In this study, patients with SHyper (the case group) and euthyroid patients (the control group) were enrolled. All patients from the two groups who were affected by multinodular goiter as preoperative diagnosis, underwent total thyroidectomy. In both groups preoperative examination included a conventional grey-scale sonography, followed by CFDS. Quantitative flow evaluation was performed measuring the maximal peak systolic velocity (PSV) at the level of intrathyroid arteries and inferior thyroid artery.

RESULTS

Patients with SHyper showed an increased thyroid vascularization both intranodular and peripheral and the mean PSV values were higher in case patients than in control subjects.

CONCLUSION

We have shown that significant changes in thyroid vascularity and blood flow velocity are already present in patients with SHyper. CFDS is a suitable technique to identify SHyper.

Hyperthyroidism increases brown fat metabolism in humans

CONTEXT

Thyroid hormones are important regulators of brown adipose tissue (BAT) development and function. In rodents, BAT metabolism is up-regulated by thyroid hormones.

OBJECTIVE

The purpose of this article was to investigate the impact of hyperthyroidism on BAT metabolism in humans.

DESIGN

This was a follow-up study using positron emission tomography imaging.

MAIN OUTCOME MEASURES

Glucose uptake (GU) and perfusion of BAT, white adipose tissue, skeletal muscle, and thyroid gland were measured using [18F]2-fluoro-2-deoxy-D-glucose and [15O]H2O and positron emission tomography in 10 patients with overt hyperthyroidism and in 8 healthy participants. Five of the hyperthyroid patients were restudied after restoration of euthyroidism. Supraclavicular BAT was quantified with magnetic resonance imaging or computed tomography and energy expenditure (EE) with indirect calorimetry.

RESULTS

Compared with healthy participants, hyperthyroid participants had 3-fold higher BAT GU (2.7±2.3 vs 0.9±0.1 μmol/100 g/min, P=.0013), 90% higher skeletal muscle GU (P<.005), 45% higher EE (P<.005), and a 70% higher lipid oxidation rate (P=.001). These changes were reversible after restoration of euthyroidism. During hyperthyroidism, serum free T4 and free T3 were strongly associated with EE and lipid oxidation rates (P<.001). TSH correlated inversely with BAT and skeletal muscle glucose metabolism (P<.001). Hyperthyroidism had no effect on BAT perfusion, whereas it stimulated skeletal muscle perfusion (P=.04). Thyroid gland GU did not differ between hyperthyroid and euthyroid study subjects.

CONCLUSIONS

Hyperthyroidism increases GU in BAT independently of BAT perfusion. Hyperthyroid patients are characterized by increased skeletal muscle metabolism and lipid oxidation rates.

The effect of voluntary iodine prophylaxis in a small rural community: the Pescopagano survey 15 years later

CONTEXT

Iodine deficiency disorders are a major public health problem, and programs have been implemented to improve iodine nutrition.

OBJECTIVE

The objective of the study was to verify the effects of voluntary iodine prophylaxis in a small rural community (Pescopagano, Italy).

DESIGN

The design of the study was the evaluation of the prevalence of thyroid disorders 15 years after a previous survey conducted before iodine prophylaxis.

SETTING

The setting for this study was a general community survey.

PARTICIPANTS

One thousand one hundred forty-eight residents were examined in 2010 and 1411 in 1995.

RESULTS

In 2010, 757 of 1148 subjects (65.9%) routinely used iodized salt, urinary iodine excretion being significantly higher than in 1955 (median 98.0 μg/L, vs 55.0 μg/L, P < .0001). The prevalence of goiter was lower in 2010 than in 1995 (25.8% vs 46.1%, P < .0001), mainly due to the reduction of diffuse goiter (10.3% vs 34.0%, P < .0001). In 2010 vs 1995, thyroid autonomy in subjects younger than 45 years old (3 of 579, 0.5% vs 25 of 1010, 2.5% P = .004) and nonautoimmune hyperthyroidism in subjects older than 45 years old (8 of 569, 1.4% vs 18 of 401, 4.5%, P = .03) were less frequent. The prevalence of hypothyroidism was higher in 2010 vs 1995 (5.0% vs 2.8%, P = .005), mainly because of an increased frequency of subclinical hypothyroidism in subjects younger than 15 years old (7 of 83, 8.4% vs 0 of 419, 0.0%, P < .0001). Accordingly, serum thyroid autoantibodies (19.5% vs 12.6%; P < .0001) and Hashimoto's thyroiditis (14.5% vs 3.5%; P < .0001) were more frequent in 2010 than in 1995.

CONCLUSIONS

In the present work, the role of voluntary iodine prophylaxis was assessed in a small rural community relatively segregated, in which genetic and other environmental factors have not substantially changed between the 2 surveys. Iodine intake strongly affected the pattern of thyroid diseases, but the benefits of correcting iodine deficiency (decreased prevalence of goiter and thyroid autonomy in younger subjects and reduced frequency of nonautoimmune hyperthyroidism in older subjects) far outweighs the risk of development of thyroid autoimmunity and mild hypothyroidism in youngsters.

First human Cerenkography

Cerenkov luminescence imaging is an emerging optical preclinical modality based on the detection of Cerenkov radiation induced by beta particles when traveling though biological tissues with a velocity greater than the speed of light. We present the first human Cerenkography obtained by detecting Cerenkov radiation escaping the thyroid gland of a patient treated for hyperthyroidism. The Cerenkov light was detected using an electron multiplied charge coupled device and a conventional C-mount lens. The system set-up has been tested by using a slab of ex vivo tissue equal to a 1 cm slice of chicken breast in order to simulate optical photons attenuation. We then imaged for 2 min the head and neck region of a patient treated orally 24 h before with 550 MBq of I-131. Co-registration between photographic and Cerenkov images showed a good localization of the Cerenkov light within the thyroid region. In conclusion, we showed that it is possible to obtain a planar image of Cerenkov photons escaping from a human tissue. Cerenkography is a potential novel medical tool to image superficial organs of patients treated with beta minus radiopharmaceuticals and can be extended to the imaging of beta plus emitters.

[Left ventricular diastolic function of patients with newly diagnosed hyperthyroidism]

OBJECTIVE

To evaluate the left ventricular diastolic function of patients with newly diagnosed hyperthyroidism.

METHODS

43 patients with newly diagnosed hyperthyroidism and 45 healthy participants were recruited to have their left ventricular diastolic function assessed with conventional echocardiography (Mitral inflow) and by indicators such as valsalva maneuver, pulmonary venous flow, Tissue Doppler imaging and Left atrial volume index (LAVI).

RESULTS

1. Hyperthyroidism patients had higher heart rate and left ventricular ejection fraction than the controls (P < 0.05). 2. There was no significant difference in LAVI (P > 0.05) between the two groups. Both groups had E/A>1. E'/A'<1 during Valsalva maneuver were found in both groups, but with significant difference (P < 0.05). The hyperthyroidism patients had significantly longer A duration than the controls (P < 0.05). 3. The hyperthyroidism patients had greater peak anterograde diastolic velocity (D), peak velociey in late diastole (Ar), duration of the Ar (Ar duration) in pulmonary venous waveforms and time difference between Ar and mitral A-wave duration (Ar -A duration) than the controls(P < 0.05). Significant difference in S/D was found between the two groups (P < 0.05). 4. Em/Am<1 and E/Em>8 was found in the patients while Em/Am>l and E/Em<8 was found in the controls (P < 0.05).

CONCLUSION

1. Hyperthyroidism patients have impaired Left ventricular diastolic function. 2. Combined use of pulmonary venous flow, Tissue doppler imaging and mitral inflow during Valsalva maneuver is more sensitive than conventional Doppler echocardiography for assessing diastolic dysfunction.

A retrospective study of the natural history of endogenous subclinical hyperthyroidism

OBJECTIVE

The treatment of subclinical hyperthyroidism is controversial because the natural history is uncertain. We undertook a retrospective study to examine the natural history of endogenous subclinical hyperthyroidism.

METHODS

Between 2002 and 2006, we identified 116 patients with thyroid-stimulating hormone (TSH) concentrations <0.4 microIU/mL but normal free thyroxin and triiodothyronine or free triiodothyronine levels and >6 months of follow-up. The medical records of these subclinical hyperthyroid patients were reviewed for demographic data, clinical outcomes, and thyroid function test results. Because the etiology of hyperthyroidism could not be identified in 57 (49%) patients, we compared patients with normal-sized or diffusely enlarged thyroid glands with patients with nodular thyroid glands. We also compared the results of patients with initial TSH levels <0.1 microIU/mL to patients with TSH levels between 0.1 and 0.39 microIU/mL, and patients age <65 years to older patients.

RESULTS

Of 116 patients with subclinical hyperthyroidism, 88 (76%) were women and 28 (24%) were men. They ranged in age from 19 to 98 years (mean = 55 years). Ninety-eight patients did not have thyroid nodules, and 18 had thyroid nodules. Follow-up ranged from 6 months to 6.5 years (median, 3.2 years). TSH reverted to normal in 58 (59%) patients without nodules; we treated only 4 (4%) of these patients for hyperthyroidism. In contrast, TSH levels in only 3 (17%) patients with nodules reverted to normal and 7 (39%) received antithyroid treatment. Atrial fibrillation was present in 8 (8%) patients without thyroid nodules and in 3 patients (17%) with thyroid nodules (P=.373). There were no significant outcome differences based on initial TSH levels or age.

CONCLUSION

We conclude that most patients with subclinical hyperthyroidism who do not have thyroid nodules rarely require antithyroid therapy but should be followed carefully.

Prevalence of incidental thyroid cancer and its ultrasonographic features in subcentimeter thyroid nodules of patients with hyperthyroidism

In patients, who undergo surgery for hyperthyroidism, many cases of incidental thyroid cancer (ITC) have been detected. In the literature, there is no study about ITC in subcentimeter nodules in these patients. We performed this study to determine the frequency of ITC in subcentimeter nodules and ultrasonographic features that can predict malignancy in the patients with hyperthyroidism. We retrospectively reviewed our database about 3114 patients, who underwent thyroidectomy in our hospital. Among 869 patients (27.9%), who were operated because of hyperthyroidism, we enrolled 337 patients, who underwent total thyroidectomy and had subcentimeter nodule [59 Graves’ disease (GD) 98 subcentimeter nodule; 278 toxic multinodular goitre (TMNG), 359 subcentimeter nodule], in this study. Twenty-five nodules with ITC and 432 benign nodules have been detected and compared for ultrasonographic (US) features. Incidental thyroid cancer detection ratio was 5.4% [10.2% (10/98) in subcentimeter thyroid nodules in individuals with GD, and 4.1% (15/359) in individuals with TMNG, P = 0.018)]. Significant differences have been observed between the groups in terms of microcalcification in US examination of malign and benign subcentimeter thyroid nodules and the ratio of anterioposterior diameter to transverse diameter (A/T) ≥1 [(OR = 5.172; 95% CI: 1.495–17.886, P = 0.015), and (OR = 5.930; 95% CI: 1.531–22.971, P = 0.007), respectively]. We detected a higher incidence of ITC in subcentimeter thyroid nodules in GD compared to TMNG. US examination of subcentimeter nodules in hyperthyroid individuals has indicated that microcalcification and ratio of A/T ≥1 are the parameters that predict malignancy.

Primary hyperthyroidism--diagnosis and treatment. Indications and contraindications for radioiodine therapy

Isotope therapy is one of the methods used in primary hyperthyroidism. The therapy is based on short-range beta radiation emitted from radioactive iodine. Radioiodine administration must always be preceded by pharmacological normalization of thyroid function. Otherwise, post-radiation thyrocyte destruction and thyroid hormones release may lead to hyperthyroidism exacerbation. Indications for radioiodine therapy in Graves-Basedow disease include recurrent hyperthyroidism after thyrostatic treatment or thyroidectomy and side-effects observed during thyrostatic treatment. In toxic nodule, isotope therapy is the first choice therapy. Radioiodine is absorbed only in autonomous nodule. Therefore, it destroys only this area and does not damage the remaining thyroid tissue. In toxic goitre, radioiodine is used mostly in recurrent nodules. Absolute contraindications for radioiodine treatment are pregnancy and lactation. Relative contraindications are thyroid nodules suspected of malignancy and age under 15 years. In patients with thyroid nodules suspected of malignancy, radioiodine treatment may be applied as a preparation for surgery, if thyrostatic drugs are ineffective or contraindicated. In children, radioiodine therapy should be considered in recurrent toxic goitre and when thyrostatic drugs are ineffective. In patients with Graves-Basedow disease and thyroid-associated orbitopathy, radioiodine treatment may increase the inflammatory process and exacerbate the ophthalmological symptoms. However, thyroid-associated orbitopathy cannot be considered as a contraindication for isotope therapy. The potential carcinogenic properties of radioiodine, especially associated with tissues with high iodine uptake (thyroid, salivary glands, stomach, intestine, urinary tract, breast), have not been confirmed.

Approach to management of the patient with primary or secondary intrathoracic goiter

Intrathoracic (substernal) goiter, depending on definition, is seen in up to 45% of all patients operated for goiter. It can either be primary (ectopic thyroid tissue detached from a cervical thyroid mass), which is very rare (1%), or (more commonly) secondary, where a portion of the goiter extends retrosternally. There is no consensus on diagnostic or therapeutic management, partly because many are asymptomatic. Classification involves functional characterization with serum TSH and morphological characterization with diagnostic imaging and cytology to rule out malignancy, which is not more common than in cervical goiters. Pulmonary function is often affected in asymptomatic individuals also. Therefore, but also because natural history is continuous growth and evolution from euthyroidism to hyperthyroidism, most experts recommend therapy. In primary as well as secondary intrathoracic goiter, the therapy of choice is total/near-total thyroidectomy and subsequent levothyroxine substitution. Data suggest that complications are only slightly more prevalent than in cervical goiters. Although levothyroxine is not recommended for goiter shrinkage, there is increasing focus on radioactive iodine as an alternative to surgery in secondary intrathoracic goiters. Here it can reduce thyroid size by on average 40% after 1 yr and improve respiratory function and quality of life. Recent studies show that recombinant human TSH, currently used off-label, can augment the radioiodine-related goiter shrinkage by 30-50%. With currently used doses of recombinant human TSH, the side effects, besides hypothyroidism, are rare and mild. Future studies should also explore the use of radioiodine in primary intrathoracic goiter and compare surgery and radioiodine, head to head.

Abnormal cardiac contractility in long-term exogenous subclinical hyperthyroid patients as demonstrated by two-dimensional echocardiography speckle tracking imaging

BACKGROUND

Subclinical hyperthyroidism is associated with cardiovascular morbidity. Recent advances in echocardiography imaging have allowed sophisticated evaluation of myocardial tissue properties.

OBJECTIVE

To investigate the myocardial effects of long-term exogenous subclinical hyperthyroidism using two-dimensional speckle tracking echocardiography imaging (2D-STE).

DESIGN

Prospective, single-blinded, placebo-controlled randomized trial of 6 months duration with two parallel groups.

PATIENTS AND METHODS

Totally 25 patients with a history of differentiated thyroid carcinoma on long-term TSH-suppressive levothyroxine (l-T(4)) substitution were randomized to persistent TSH-suppressive l-T(4) substitution (low-TSH group) or restoration of euthyroidism. Additionally 40 euthyroid controls were studied. RESULTS (PROPOSAL): At baseline, the group of patients showed normal left ventricular (LV) systolic function but impaired diastolic function as assessed with conventional echocardiographic parameters. Importantly, 2D-STE analysis demonstrated the presence of subclinical LV systolic and diastolic dysfunction with impaired circumferential and longitudinal strain and strain rate at the isovolumic relaxation time. After restoration of euthyroidism, a significant improvement in LV systolic and diastolic function as assessed with 2D-STE strain was observed.

CONCLUSION

Prolonged subclinical hyperthyroidism leads to systolic and diastolic dysfunction, which is reversible after restoration of euthyroidism. 2D-STE is a more sensitive technique to evaluate subtle changes in LV performance of these patients.

[Minimally invasive parathyroidectomy for treatment of primary hyperparathyroidism caused by parathyroid adenoma]

BACKGROUND

Minimally invasive parathyroidectomy (MIP) is frequently used for the treatment of primary hyperparathyroidism (PHPT) caused by a single adenoma. This method depends on preoperative localization of the tumor by a sestamibi scan, cervical ultrasound, and intraoperative parathyroid hormone (PTH) measurements. When the sestamibi scan is negative, the classical 4-gland exploration is used instead of MIP.

AIMS

a. To evaluate the effectiveness of MIP for treatment of PHPT caused by adenoma. b. To evaluate the use of PTH selective venous sampling (PTH-SVS) in patients with negative sestamibi scintigraphy.

METHODS

MIP was performed in all patients in whom an adenoma was diagnosed by sestamibi scan and US. When the sestamibi scan was negative, PTH-SVS was performed preoperatively for localization of the adenoma.

RESULTS

Parathyroidectomy was performed in 541 patients, 458 with PHPT and 83 with secondary hyperparathyroidism. In 345 of 380 patients (90.8%) with an adenoma, MIP was performed, and in 92 of these patients the operation was performed under local anesthesia. A total of 444 (97.0%) of the patients with PHPT were cured by the surgery. In 56 patients with a negative sestamibi scan, PTH-SVS was used preoperatively for localization of an adenoma. In 30 of these cases (53%) MIP was successfully performed in spite of a negative sestamibi scan.

CONCLUSIONS

MIP is the treatment of choice for PHPT caused by a single adenoma. When the preoperative sestamibi scan is negative, the authors recommend the use of PTH-SVS for preoperative localization. This resulted in 53% successful MIP in patients with a negative sestamibi scan.

Investigation of biokinetics of radioiodine with a population kinetics approach

The dosimetric studies required for planning individually tailored radioiodine therapy of benign thyroid pathologies may be too complex and time-demanding for many ordinary nuclear medicine departments. In this work, a preliminary population kinetics approach was applied to a model structure for iodine biokinetics in order to identify those model features that actually need to be individually investigated, in order to simplify the protocol for data collection in patients. Data from 29 patients undergoing radioiodine therapy for the treatment of the autonomous nodule syndrome were used in the analysis. The greatest inter-individual variations were observed in the parameters describing the transformation of iodide into organic iodine in the thyroid and in the kinetics of the organic form.

The utility of radioiodine uptake and thyroid scintigraphy in the diagnosis and management of hyperthyroidism

BACKGROUND AND OBJECTIVES

The value and practice of thyroid radionuclide imaging in the diagnosis and management of hyperthyroidism is unsettled. Our objectives were to determine the influence of thyroid uptake and scintigraphy on the diagnosis of hyperthyroidism and the prediction of outcome following radioiodine therapy.

PATIENTS AND DESIGN

We reviewed records and scintigraphic studies on 881 hyperthyroid patients carried out between 2000 and 2007. The agreement between the clinical and scintigraphic diagnosis was evaluated by kappa statistics. We determined the relationship between 4-h (123)I uptake and the outcome of (131)I treatment in 626 patients. A multiple logistic regression model was used to determine variables influencing treatment outcome in 1 year.

RESULTS

The diagnostic categories were Graves' disease (GD, n = 383), toxic multinodular goitre (n = 253), solitary toxic nodule (n = 164) and Graves' disease coexisting with nodules (n = 81). The mean age of the patients was 58 +/- 17, (M:F 160:721). There was good agreement between clinical and scintigraph diagnosis (K = 0.60, 95% CI 0.57-0.64, P < 0.001); and they were correctly matched in 74%; mismatched in 6% and indeterminate in 20% of patients. Treatment outcome was not associated with scintigraph diagnosis (P = 0.98) or radioiodine uptake at 4 h (P = 0.2). The use of antithyroid medications before treatment predicted treatment failure (odds ratio 2.0, 95% CI 1.2-3.6, P = 0.01).

CONCLUSION

Thyroid scintigraphy and uptake studies did not influence diagnosis or treatment outcomes in most cases of hyperthyroidism. Our findings in this retrospective study do not justify their routine use. Selective scanning will reduce cost and exposure to radioisotopes without compromising diagnostic accuracy or treatment outcomes.

Hypercalcemia due to Graves' disease in a patient with thyroid hemiagenesis

Thyroid hemiagenesis is a rare anomaly due to failure of development of one thyroid lobe during embryological life. A lot of thyroid disorders may accompany thyroid hemiagenesis. In this report, we present a case of thyroid hemiagenesis, who had moderate hypercalcemia due to Graves' disease. A 43-year-old woman presented with weight loss of more than 5 kg within one month, heat intolerance, and increased sweating. For the past month, she had been troubled by intermittent symptoms of vomiting, thirst, and constipation. On examination, she had tachycardia with no signs of dehydration. Pulse rate was 110 per minute. She had fine tremor, proximal muscle weakness, and asymmetric smooth goiter and hyperplasia in the right thyroid gland. Thyroid function tests confirmed the diagnosis of hyperthyroidism. Although hypercalcemia may be detected in patients with thyrotoxicosis, to the best of our knowledge, this is the first case report of thyroid hemiagenesis accompanying hypercalcemia due to thyrotoxicosis.

Use of ultrasound to distinguish between fetal hyperthyroidism and hypothyroidism on discovery of a goiter

OBJECTIVES

To determine whether sonography can be used to distinguish hyperthyroidism from hypothyroidism in pregnancies with fetal goiter.

METHODS

This was a retrospective study of 39 cases of fetal goiter. The majority of the mothers had Graves' disease. Fetuses were scanned for the existence of a hypertrophic thyroid gland (goiter) beginning at 22 gestational weeks. Once a goiter was diagnosed, different echographic features were analyzed and the effect of chosen treatment on fetal thyroid development was monitored.

RESULTS

On color Doppler, 68.8% of hypothyroid goiters had a peripheral vascular pattern vs. 20% in cases of fetal hyperthyroidism (P = 0.0574). No hypothyroid goiter presented central vascularization whereas half the hyperthyroid goiters did (P = 0.0013). Fetal tachycardia was a good indicator of hyperthyroidism (57.1% v.s 6.3%; P = 0.0055). Delayed bone maturation was seen in hypothyroid goiters (46.9% vs. 0%; P = 0.0307), while advanced bone maturity was specific to hyperthyroid goiters (85.7% vs. 0%; P < 0.0001). Lastly, an increase in fetal movement was observed in cases of fetal hypothyroidism (43.8% vs. 0%; P = 0.0364).

CONCLUSION

Based on the color Doppler pattern of goiter, fetal heart rate, bone maturation and fetal mobility, we established an ultrasound score to predict fetal thyroid function in cases of fetal goiter.

The prevalence of thyroid dysfunction in elderly cardiology patients with mild excessive iodine intake in the urban area of São Paulo

OBJECTIVES

To evaluate the prevalence of thyroid dysfunction in elderly cardiac patients in an outpatient setting.

SUBJECTS AND METHODS

A total of 399 consecutive patients (268 women, age range 60-92 years) who were followed at Heart Institute were evaluated for thyroid dysfunction with serum free T4, TSH, anti-Peroxidase antibodies, urinary iodine excretion measurements and thyroid ultrasound.

RESULTS

Hyperthyroidism (overt and subclinical) was present in 29 patients (6.5%), whereas hypothyroidism (overt and subclinical) was found in 32 individuals (8.1%). Cysts were detected in 11 patients (2.8%), single nodules were detected in 102 (25.6%), and multinodular goiters were detected in 34 (8.5%). Hashimoto's thyroiditis was present in 16.8% patients, most of whom were women (83.6%). The serum TSH increased with age and was significantly higher (p= <0.01) in patients, compared to the normal control group. No significant differences in serum TSH and free T4 values were observed when patients with atrial fibrillation (AF) where compared with those without arrhythmia. The median urinary iodine levels were 210 microg/L (40-856 microg/L), and iodine levels were higher in men than in women (p<0.01). Excessive iodine intake (urinary iodine >300 microg/L) was observed in one-third of patients (30.8%).

CONCLUSIONS

Elderly patients have a higher prevalence of both hypo- and hyperthyroidism as well as thyroid nodules when compared with the general population. About one-third of the older patients had elevated urinary secretion of iodine and a higher prevalence of chronic Hashimoto's thyroiditis. It is recommended that ultrasonographic studies, tests for thyroid function and autoimmunity should be evaluated in elderly patients.